package org.springframework.boot.autoconfigure.netty.support;

public class PlaceholderParser {

  private static String placeholder = "*";

  /**
   * 将字符串text中由openToken和closeToken组成的占位符依次替换为args数组中的值
   *
   * @param openToken
   * @param closeToken
   * @param text
   * @param args
   * @return
   */
  private static String parse(String openToken, String closeToken, String text, Object... args) {
   /* if (args == null || args.length <= 0) {
      return text;
    }*/
    int argsIndex = 0;
    if (text == null || text.isEmpty()) {
      return "";
    }
    char[] src = text.toCharArray();
    int offset = 0;
    // search open token
    int start = text.indexOf(openToken, offset);
    if (start == -1) {
      return text;
    }
    final StringBuilder builder = new StringBuilder();
    StringBuilder expression = null;
    while (start > -1) {
      if (start > 0 && src[start - 1] == '\\') {
        // this open token is escaped. remove the backslash and continue.
        builder.append(src, offset, start - offset - 1).append(openToken);
        offset = start + openToken.length();
      } else {
        // found open token. let's search close token.
        if (expression == null) {
          expression = new StringBuilder();
        } else {
          expression.setLength(0);
        }
        builder.append(src, offset, start - offset);
        offset = start + openToken.length();
        int end = text.indexOf(closeToken, offset);
        while (end > -1) {
          if (end > offset && src[end - 1] == '\\') {
            // this close token is escaped. remove the backslash and continue.
            expression.append(src, offset, end - offset - 1).append(closeToken);
            offset = end + closeToken.length();
            end = text.indexOf(closeToken, offset);
          } else {
            expression.append(src, offset, end - offset);
            offset = end + closeToken.length();
            break;
          }
        }
        if (end == -1) {
          // close token was not found.
          builder.append(src, start, src.length - start);
          offset = src.length;
        } else {
          ///仅仅修改了该else分支下的个别行代码
          String value = (argsIndex <= args.length - 1) ?
                  (args[argsIndex] == null ? placeholder : args[argsIndex].toString()) : placeholder;
          builder.append(value);
          offset = end + closeToken.length();
          argsIndex++;

        }
      }
      start = text.indexOf(openToken, offset);
    }
    if (offset < src.length) {
      builder.append(src, offset, src.length - offset);
    }
    return builder.toString();
  }

  public static String parse0(String text, Object... args) {
    return PlaceholderParser.parse("${", "}", text, args);
  }

  public static String parse1(String text, Object... args) {
    return PlaceholderParser.parse("{", "}", text, args);
  }

  /**
   * 使用示例
   *
   * @param args
   */
  public static void main(String... args) {

    System.out.println(PlaceholderParser.parse1("/test/abc/efg"));
    System.out.println(PlaceholderParser.parse1("/test/{path1}/{path2}"));

  }
}